International Dialling Format ...
No, but the dial pad shows a flag of the country I'm dialling, so I presume that bit is taken care of?
So far I've only played with SMS text in New Zealand, where I live, and the dial pad - to type in the number - has the NZ flag at the top,so I don't then put 64 in front of the number, and I can make voice calls OK to both landlines and cellphones, it's just the SMS ones that don't get through.
A friend has suggested that my Virus protection software is causing the problem, so I'll see if I can get some clue there.